looking at the krypt 4200 equalizer, but wondering if there is anything a little cheaper that will do what i want.

here is what i am looking to get out of it,
1)volume control for tower speakers and separate for interior boat speakers (2 zones)
2)equalizer for both seperate zones, interior speakers and tower speakers
3)sub control

also i have a sub and amp for the sub and tower speakers and seperate amp for the tower speakers. not sure how to hook all this up to the equalizer and head unit. but i guess i can worry about that once i get the right equalizer.